Investigation of premature failure mechanism in pavement overlay of national highway of Bangladesh

2022 ◽  
Vol 318 ◽  
pp. 126194
Author(s):  
Md. Joynul Abadin ◽  
Kimitoshi Hayano
Keyword(s):  
Failure Mechanism ◽  
Premature Failure ◽  
National Highway ◽  
Pavement Overlay

Analysis of Premature Rip-Off Failure Mechanism of Reinforced Concrete Beams Strengthened with FRPs

2006 ◽  
Vol 324-325 ◽  
pp. 1325-1328
Author(s):  
Cheol Woo Park ◽  
Jong Sung Sim ◽  
Sung Jae Park
Keyword(s):  
Reinforced Concrete ◽  
Failure Mechanism ◽  
Failure Load ◽  
Reinforced Concrete Beams ◽  
Shear Stresses ◽  
Strengthening Effect ◽  
Rc Beams ◽  
Premature Failure ◽  
Cfrp Plate ◽  
Proposed Model

Various types and forms of FRP materials have been applied for structural strengthening of reinforced concrete (RC) beams. When CFRP plates are used, however, a premature failure used to occur before strengthening effect appears adequately. This is primarily due to the rip-off of CFRP plate attached on RC beams. Despite of numerous studies on the rip-off failure of externally strengthened RC beams, the failure mechanism is not clearly explained yet. Investigations from the literatures have shown that the rip-off failure is dependant on vertical and shear stresses at the level of main reinforcements in RC beams. This study suggests an analytical model to investigate the ripoff failure load based on the stresses at the level of main reinforcements. The proposed model is relatively simple and produces very comparable results to the test data. Therefore, it is anticipated that the proposed model can be successfully used to provide further information on the rip-off failure mechanisms and its prevention.

scholarly journals Corrosion Behavior and Failure Mechanism of Prestressed Rock Bolts (Cables) in the Underground Coal Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qiong Wang ◽  
Fengnian Wang ◽  
Aiwu Ren ◽  
Rui Peng ◽  
Jian Li
Keyword(s):  
Failure Mechanism ◽  
Corrosion Behavior ◽  
Coal Mine ◽  
Pitting Corrosion ◽  
Service Time ◽  
Outer Diameter ◽  
Uniform Corrosion ◽  
Rock Bolts ◽  
Premature Failure ◽  
Underground Coal Mine

Premature failure of rock bolts (cables) due to stress corrosion cracking (SCC) is a phenomenon that has been reported to occur in the underground environment. In the 1990s, many failure accidents of bolts which occurred in the United Kingdom were caused by SCC [1]. In this study, the corrosion behavior and failure mechanism of rock bolt (cable) samples obtained from the underground coal mine were examined and discussed. Macroscopic observation and weight loss tests were carried out for the bolts’ corrosion characteristics without failure. The results show that the bolts with short service time (1.5–2 yrs) underwent uniform corrosion. However, bolts with longer service time (3–8 yrs) experienced different pitting corrosion degrees. The corroding degree of different parts of bolt samples shows the following decreasing trend: bolt head > bolt end > free section. The absolute corrosion degree increased with the service time, while the corrosion rate was the highest in the early stage and dropped down in the later stage. At the same time, the macro- and micromethods were used to analyse the failure mechanism in the broken cable sample. Failure of one cable sample with a medium service life (6 yrs) was found to be controlled by the SCC. It was induced by long-term action of O, Cl, and S in the surrounding rock environment and resulted in pitting corrosion. The pitting corrosion reduced the outer diameter of the rock cable and its bearing capacity, leading to the final fracture.

scholarly journals Corrosion Behavior and Failure Mechanism of Rock Bolt(Cable) in Underground Coal Mine

2020 ◽  
Author(s):  
Qiong Wang ◽  
Aiwu Ren ◽  
Songyang Yin ◽  
Mengyi Li
Keyword(s):  
Failure Mechanism ◽  
Corrosion Behavior ◽  
Coal Mine ◽  
Pitting Corrosion ◽  
Service Time ◽  
Rock Bolt ◽  
Outer Diameter ◽  
Uniform Corrosion ◽  
Premature Failure ◽  
Underground Coal Mine

Abstract Premature failure of rock bolt (cable) due to stress corrosion cracking (SCC) is a phenomenon that has reported to occur in underground environments. In this study, the corrosion behavior and failure mechanism of rock bolt (cable) samples obtained from underground coal mine were examined and discussed. Macroscopic observation and weight loss test were carried out for the corrosion characteristics of the bolts without failure. It is found the corrosion form is uniform corrosion for the bolts with short service time (S-1, S-2). But for the bolts with longer service time (S-3, S-4 and S-5), experience different degrees of pitting corrosion and the number of corrosion spots on the surface of the sample increases with increase of the service time. The corrosion amount of different parts of the bolts shows the rule of bolt head > bolt end > free section, and the corrosion amount increases year by year with the service time, but the corrosion growth rate is fast in the early stage and slows down in the later stage. At the same time, the failure mechanism of the failure sample S-6, which has been in service for 6 years, was analyzed with macro and micro methods. The results show that S-6 have been in O, Cl and S surrounding rock environment for a long time, resulting serious pitting corrosion and spalling of the surface material of the steel strand, which reduces the outer diameter of the rock cable and its bearing capacity, finally leads to the instantaneous SCC fracture of the sample S-6.

Coiled Tubing Vibration and Premature Failure

2021 ◽  
Author(s):  
Bruce Reichert ◽  
Sebastian Cravero ◽  
Martin Valdez ◽  
Jorge Bunge
Keyword(s):  
Dynamic Response ◽  
Failure Mechanism ◽  
Horizontal Wells ◽  
Premature Failure ◽  
Material Response ◽  
The Past ◽  
Coiled Tubing ◽  
Axial Vibrations ◽  
Possible Cause ◽  
Tubing Material

Abstract A new coiled tubing (CT) failure mechanism has appeared in the past two to three years. The failures occur in CT strings used for frac plug milling in extend reach horizontal wells. The objective of this paper is to investigate a possible cause for these failures. The primary emphasis is analyzing the dynamic response of the CT to axial vibrations induced by a downhole extended reach tool [1], and the resulting tubing material response leading to failure.

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

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